| Name |
Larry Pratt Pratt |
| Country |
USA |
| Email |
lpratt@whoi.edu |
| Co-Author(s) |
L. J. Pratt, I. Rypina, T. M. Ozgokmen, P. Wang |
| Submit Time |
2014-02-24 20:40:52 |
Session |
Special Session 118: Transport barriers in unsteady fluid flows
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| Contents |
| We investigate the existence and stability of transport barriers in a fully three-dimensional Navier-Stokes flow in a rotating cylinder. This idealization of an isolated ocean eddy is driven from above by a surface stress and has both horizontal swirl and overturning. The invariant tori that act a material barriers in the steady, axi-symmetric case break when a symmetry-breaking disturbance becomes larger. Chaos is induced either by resonance or by the breakup of the central axis streamline into stable and unstable manifolds in 3D. We identify several distinct regimes of Lagrangian behavior and map these out in terms of the Ekman and Rossby numbers. We also use Eulerian constraints such as the Taylor-Proudman theorem to motivate the differences. We also calculate the acceleration of the stirring rate due to the chaos and find some surprising trends. A formula for the resonance width is derived, and this and a version of the KAM theorem are used to interpret our findings. We explore the diffusive affects of background turbulence on the integrity of the barriers and the rate of stirring. |
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